1. Field of the Invention
This invention relates to a method and apparatus for producing and dispensing aerated and/or blended food products. While the invention may be used to produce a variety of products, it has particular application to the production and dispensing of frozen confections such as ice cream and frozen yogurt. Consequently, we will describe the invention in that context. It should be understood, however, that various aspects of the invention to be described also have application to the making and dispensing of various other food products.
2. Description of the Prior Art
Aerated frozen food products generally require the mixing of selected liquid ingredients with a prescribed volume of air and freezing of the resultant mixture and dispensing of the finished product. The desirability of the finished product is often related directly to the manner and to the degree in which the air is metered and blended with the liquid ingredients of the mixture, referred to as overrun, and the manner in which the blended mix is frozen and then dispensed. The prior art is replete with examples of apparatus for dispensing ice cream and other semi-frozen dairy products such as soft ice cream and frozen yogurt.
Conventionally, such machines are usually dedicated to dispensing one or two flavors of product and, in some cases, a combination of the two. For example, in an ice cream shop, there may be one machine with two separate freezing chambers for making and dispensing chocolate and vanilla ice cream, a second two-chamber machine for making and dispensing strawberry and banana ice cream, a third machine dedicated to making and dispensing coffee and frozen pudding flavors, and so on. The reason for this is that each chamber typically contains a volume of ice cream greater than is required for a single serving. In order to dispense a different flavor ice cream, that chamber must be emptied and cleaned before the new flavor can be made in that chamber and appear at the outlet of the dispenser. Additionally, the vat of preflavored mix from which the frozen product is made must also be very clean. While high volume ice cream shops and confectionery stores may have sales to justify the presence of several dispensing machines dispensing many different products and flavors, smaller sales outlets can usually only afford one or two such machines and are thus restricted in the number of flavors that they can offer to customers.
Further, because the product is typically formed in a quantity that is greater than that to be dispensed at any one serving, the excess product remains in the chamber after formation and until additional servings draw it down. The excess is thus subjected to further freezing which promotes crystallization. Because of the relatively large quantity of the premixed flavors, and the continuous freezing of several quarts of the product, the freshness and palatability of the product may be adversely affected in outlets with relatively slow sales of the product.
Another disadvantage of the prior dispensers is that they have many interior surfaces and moving parts that are difficult and time consuming to clean and maintain at the end of each day or at intervals prescribed by local Health Department regulations. Each dispenser must be purged of any remaining product, and it's chamber walls, pumps and other internal parts cleaned thoroughly to prevent growth of bacteria that could contaminate the product being delivered by the dispenser. Not only is the cleaning operation expensive in terms of down time, it is also costly in terms of product waste and is an unpleasant and difficult job to get employees to do properly.
U.S. Pat. No. 5,433,967 discloses a method and apparatus for producing and dispensing an aerated product which includes a mixing chamber having a first inlet for receiving a liquid, a second inlet for receiving a gas, and an outlet leading to a continuous tube which has a relatively small cross section. The tube has one end positioned to receive the fluid effluent from the mixing chamber outlet and its other end is spaced from that outlet so that the effluent is subjected to confined turbulent mixing in the tube until the fluid product is discharged from the other end of the tube. If that product is to be cooled, the tube leads to a cooling zone or surface which cools and at least partially freezes the liquid product issuing from that tube. The apparatus disclosed there is especially suitable for making and dispensing frozen yogurt and ice cream and allows for the service of individualized fresh product portions in a variety of flavors.
U.S. Pat. No. 5,727,713 discloses a dispenser product supply unit which includes a pressurizable container for containing a product liquid or base and having an opening leading into one end of a conduit. Formed integrally in the conduit is a mixing chamber at which a gas may be added to the liquid, followed by an elongated tube for causing turbulent flow of the mixed fluids. Side branches from the conduit may also be present for introducing one or more flavors into the fluid flowing through the conduit. The opposite or outlet end of the conduit may be coupled to a distribution manifold that can distribute the aerated liquid issuing from the turbulence tube onto a freezing surface as a relatively thin layer. The container, conduit and side branches constitute a one-piece disposable structure which is especially suitable for producing and dispensing flavored dairy products from an associated dispensing apparatus in an efficient and sanitary manner.
While the apparatus described in the above patents, the contents of which are hereby incorporated herein by reference, have existed separately in the prior art, until now no way has been found to combine them into a single machine capable of efficiently and economically making and dispensing different frozen food confections in a wide variety of flavors and in different formats, e.g. as a cup or cone.